MVC Optional Parameter Default Value

Question

I have the following MVC Action:

[ActionName("order-brochure")]
public ActionResult OrderBrochure(int brochureId, bool isModal = true)
{
    return View(HomeModelBuilder.BuildOrderBrochureModel(brochureId, isModal, false));
}

Where isModal is an optional parameter

Is there any other way to set the default for this other than using bool isModal = true within the method as my company uses code analysis and this fails giving a CA1026: default parameters shouldn't be used

However, I can't override the method as you can't have two actions with the same name as you'll get an error along the following lines:

The current request for action 'order-brochure' on controller type 'HomeController' is ambiguous between the following action methods: 
System.Web.Mvc.ActionResult OrderBrochureModal(Int32, Boolean) on type MarshallsCoUkCommercial.Website.Controllers.HomeController
System.Web.Mvc.ActionResult OrderBrochure(Int32) on type MarshallsCoUkCommercial.Website.Controllers.HomeController

And if I use

public ActionResult OrderBrochure(int brochureId, bool isModal)

Setting isModal to UrlParameter.Optional

I can't test to see if isModal is null as it will always be set to false

What about public ActionResult OrderBrochure(int brochureId, bool? isModal)? Now you can test it to see if it's null. — Andrei V
– Andrei V, Commented Feb 21, 2014 at 11:54
Weird I tried it as a nullable bool before and it just crashed, just tried it again and it now works — Pete
– Pete, Commented Feb 21, 2014 at 12:04

trailmax · Accepted Answer · 2014-02-21 12:01:37Z

2

Apparently this rule is outdated and should not be applied to C# 4.0 and above. See this discussion for similar question.

I would say just disable this rule, as it makes no sense in MVC4.

However, suppressing the rule might not be compliant with your company rules, then you'd have to work around that. (These rules are silly, when you have to hack around some outdated crap like that!)

One of the options is to have a custom rule for the every case like that: specify default value for optional param. (Sorry, can't find implementation for that quickly)

Or, as already suggested go with nullable boolean

public ActionResult OrderBrochure(int brochureId, bool? isModal)

and then in your method check for null on isModel.

answered Feb 21, 2014 at 12:01

trailmax

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1 Comment

Pete Over a year ago

I thought it made no sense with MVC4, I've just sent an email to my boss asking him to disable it! Thanks

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